The prior electrical screwdrivers have not been capable of powering off automatically when a screw is tightened. The above-mentioned purpose can be achieved only by manually switching off the screwdriver. Therefore, good control over the operation of a conventional electrical screwdriver will greatly depend upon the experiences of users in this field. It will apparently reduce working efficiency as well as the accuracy and quality of screwing.
It is therefore, the applicant of this invention to develop an electrical screwdriver which can be capable of powering off automatically when a screw is tightened to eliminate disadvantages existing in prior art.